Well, starting with a mutation, a mutation is a disruption in a genetic sequence in an organism that codes for a particular trait. The genetic sequence my be altered by radiation or disease, or in todays modern scientific laboratories, by genetic engineering by scientists. The mutation may produce a specific adaptation that makes the species more viable in its struggle to dominate the species. For example, the multiplicity of beak types in Darwins finches show the tremendous range of beaks suited for different tasks. In the plant world, hardly anything can match kudzu in its ability to dominate southern, tropical landscapes. So a mutation, whether naturally occuring or induced artificially by genetic engineering, influences and produces adaptations that may make some branches of the species more dominant, more able to compete in the struggle to live and propagate.